T offiff



Patented June 28, 1927.

'oLAv BERG, or ra'rnnson, AND MAX rmnorr,

OF CLIFTON, NEW JERSEY.

PROCESS OF WEIGHIING FIBERS.

No Drawing.

This application relates to the weighting of fibers in general, but more particularly to the weighting of silk; weighting being the term of the art for a process of increasing the size and weight of fiber. l/Vhile the present process is particularly intended for the treatment of natural silk, it is not limited thereto.

Under methods now in vogue and employed in the past, salts of tin, iron and, to a very limited extent, of bismuth and aluminum, have been recognized as the only metal salts which could be used in a practical commercial way for the weighting of silk. Of these, only the salts of tin and iron have been employed generally; and iron only in the case of black or dark colored goods. Heretofore, the extent of weighting has been limited because after a certain amount of weighting material has been taken up, the fiber is injuriously affected. There is a practical limit in the prior art processes to the amount of mineral matter which the fiber will take up without injuring its phys- 25 ical properties. Usually the result was a compromise between increase in quantity and decrease in quality. While by such known processes it has been possible to add from ten per cent up to one hundred and thirty ten per cent above par, above ten per cent the effect on the fibers is markedly injurious, taking away both-elasticity and strength and making them brittle and tender and subject to deterioration with age. While the amount of. loading permissible in producing commercial silk without undue forfeiture of quality varies with the silk and with the operator, twenty-five per centis often considered a practical limit. V

The purposes of the present invention are to improve upon former methods and to provide an inexpensive and simple method by which it is possible to weight silk or other fibers to any desired extentrnot only without materially impairing or destroying the essential or desirable qualities thereof, but in fact improving them. Another ob= jest to provide a new material produced by this process; 1, in he Application filed February 25, 1926. Serial No. 90,701.

embodiment of our invention now known to us, is a fiber possessing all the textile qualities of silk but in which silk substance may be only a minor fraction; the major being composed of tin and lead oxides and P 0 (phosphoric acid) in some form of combi- 5 nation with each other and with the silk substance. The result is a sort of composite fiber which, although silky, flexible and strong, and homogeneous under the microscope, is nevertheless largely mineral matter. The lead in the fiber is fixedly held and is insoluble. The new fiber, although containing in some embodiments as high as two hundred per cent weighting, largely PbO, does not yield lead to boiling vinegar (three per cent acetic acid) or to any of the liquids with which silk is likely to come in contact in the dye-house or in use.

One phase of the invention relates to the discoverey of a method by which there is created in the silk, an afiinity for lead compounds, making it possible to combine lead compounds with the fibers in such a way as to materially increase its weight and the size of the fiber; that is, so as to give a composite fiber in. which a large fraction of the fiber is lead in some form; this composite fiber having the desirable properties of ordinary weighted silk without its usual disadvantages and having certain new and use ful advantages of its own. In this method the silk or other fibrous material is first treated with a substance which the fibers readily take up and which gives the fibers the ability to take up lead compounds after which the latter material is added, for instance, as lead acetate. So to speak, the fiber is mordanted with materials giving it an atlinity for lead.

A special feature of the preliminary or primary weighting operations, by which the atfinity for the heavier metallic compounds, is created. is that they may be the same as heretofore have been emnlo ed in tinweighting and like pro paratus and the inater l be employed '1 ill first bath, namely. a solution of tin tetrachloride (stannic chloride) or of pink salt, which is a combination of tin tetrachlm-ide and ammonium chloride. A solution of sodium stannate has been used in tin-weight inn. So have potassium ammonium stannates been used but are not better than sodium stannate. Any o't these materials used in aqueous solution deposit on the silk a certain amount oftin in a form equivalent to st-annic oxide, S110 The fibrous material, which in the case of silk may be either in the gum, de-gunnncd or partially de-gm'nmed and may be in the form of fibers, or woven or knitted fabric, is passed first into a bath of a solution of stannie chloride (Such), then through a wash o'l water, then into a fixing bath of a sodium phosphate, such as (ii-sodium, (Na HPO L1QH O), followed by another water wash. As is usual in old and well known tin-weighting processes, this second wash may he followed by a treatment in a weak solution ot acetic acid at a predetermined temperature. In the first bath, which maybe a cold one, as is well known, a cer tain amount of weight is added to the fiber and excess material, stannic chloride and HCl, is removed in the first water wash, which'also may be cold, the latter also apparently having to some extent a hydrolyzinn' ettect on the tin chloride remaining in the fiber; breaking it up in a way equivalent. to the production'o'l tin oxide remaining with the fiber and hydrochloric acid which goes oil with the water.

- In place of sodium phosphate, other alkaline salts or carbonates may be used in what we have termed the fixing bath, the temperature of this bathbeing such as hitherto used in the art. In using a phosphate bath, a large amount of P' O is taken up. Astar as our present knowledge goes, sodium phosphate is the best substance to use. In the weighting and fixing baths, the weight is increased, usually about ten percent. The wash following the fiXin bath may be either cold or warm. These steps are old and well known in the art. and may be and usually are repeated a number of times. These steps constitute the first stage of our complete process which we shall herein designate the A stage.

lVe have discovered that the A stage treatmerit, weigitinc' the fibers with tin salts and fixing them, imparts to the fiber thus treated an atiinity for other metallic compounds. \V'e have found that the fibers can be further weighted to practically. :U'B 'ClGSlYQr l extentby'subjecting them to the-treatment hereinatter described as the B and C stages. In the best embodiment of our invention at present known to us, the further weighting is done with the aido't lead compounds, using any suitable soluble lead salt generally lead acetate.

It is possible to use lead salts tor this purpose bccause ot the fact that the preparatory treatments described create in the material the property of ta ring up lead (PbO) lrom them. in the tanhodii'i'icnt of our invention herein shown and described, we use a solution of lead acetate, which may be commercialsugar of lead or a more basic acetate. This, "followed by alter wash is the B stage of: treatment. This B stage increases the weight ot the material usually from20*pcrccnt to per cent, depoudi, upon the amount of added materials already in the fiber. The lead acetate t'tu'nii'gl'ieslea-d which combines or unitcqkwith the associated fiber and mineral matters and, forms an insoluble compound. Theprocess may term? note here. I

We prefer to followthis treatment by the C stage, which is subjecting' the fibers to cold bath ot sodium phosphate solutioi'i, after which they may be given another wash in water. Sodium phosphate the best salt to use at this stage. A treatment with sodium phosphate much improves the fiber prepared by the present process so far described. This C stage not only improves the appearance and the scroop ot the iiber, but imparts to it the'propert of being; able to take up more lead. coi'npounds it it is again submerged in the lead acetate solution. Thus the B stage may he 1'01')0-( artter the C stagge -again and again, it desired. The permanency with which the lead is held in the tiber is increased by this phosphate a:l ter-treatment.

3y thus alternately adding; weight and creating an at'finity or avidity tor 'l urther weighting material, it is possible to add to the weight ol the fiber at an increasing rate,

to an extent greatly in xcessot' what has been possible heretofore.

As a concrete example of a way in which we have practiced this in *ention successfully, we have placed silk taln'ies in a solution of stannic chloride, tin-Ch at 20 Bauni for approximately one hour al'terv-ihich they were removed and washed. Then we placei'l the :talu'ics in a solution oi sodium phosphate of 7 Baum and at a tempera lure of 150 l". where they were permitted to remain tor ap proximately one hour when they were removed and washedin clear water; 'lhese steps were repeated threetin'ios, more or less as desired.

After the last washing the 'l'ahrics were placed in whathas been called a 3% solution ol jacetic acidat a temperature of 160 i More accurately, the strength of th s bath has been determined by adding) acetic acid to the extent oil 3% (it. the weig t of the fabrics treated, to the water of rnis bath.

The fabrics were allowed to remain in this bath for approximately one half hour and then treated with cold water.

This constitutes the preparatory treatment orthe A. stage of our complete procsee, all of which is old and is a usual way of practicing the well known tin-weight ing" process.

7 the ll stage of ill process we used a solution of acetate of lead of 2 to 3 degrees Baum at 150 F. and permitted the fabrics to remain in it for one hour, after which they were washed.

As the C of our process the fabrics were placed in a cold solution of sodium phosphate for one half hour and then removed and dried.

The process may be carried on so as to produce practically any desired increase in weight with the important advantage of effecting increase in weight not only without injuring the material or causing any substantial deterioration in the mechanical properties or appearance of the fiber either immediately, in subsequent use or from age, but with some actual improvements in these respects. The fibers retain their flexibility and strength, as well as their appearance and their ability to take on dyes or be otherwise treated. Dyeing is more even and better and the elasticity is increased. The weighted material, furthermore, has good lasting and wearing qualities, the desired scroop, is non-poisonous, and is insoluble.

in using a solution of sodium phosphate as the fixing bath, a considerable amount of P 0 is taken up, as stated, and the presence of this P 0 is advantageous in making the material of the present invention. But the P is not necessarily added at this stage, since the order of steps may be changed. It is, for instance, possible to treat the silk with a tin solution, wash in a fixing bath and follow directly with a solution of lead acetate, treating this, in subsequent stages, with sodium phosphate.

Another important advantage of the invention that this improved lead-weighting process is applicable to such goods as are already manufactured so that a manufacturer may make one quality of goods, for

sample by spinning or weaving, and by giving such goods different amounts of weight by this process, may make them into any desired number of different grades by weight. l urthermore, a ncw'and useful material is made by this process.

The description which we have made of this invention is for illustrative purposes only, as we realize that many variations in the steps and the chemicals employed may be used without departing from the scope of the invention. Therefore, we intend no limitations other than those imposed by the appended claims.

What we claim is:

l. A process for weighting silk fabrics which comprises placing the fabrics in a solution of stannic chloride of 20 Baum for approi-Liniatelyone hour, then washing the fabrics, treating the was-lied fabrics with a solution of sodium phosphate of 7 Baume at a temperature of 150 for approximately one hour, then washing the fabrics, treating the washed fabrics with a 3% solution of acetic acid at 160 F. for one half hour, washing the fabric with cold water, treating the fabric with a solution of lead acetate of approximately 3 Baum at a temperature of 150 F. for one hour and then after washing treating the fabrics with a cold solution of sodium phosphate for one half hour.

2. A process for weighting silk fabrics which comprises placing the fabric in a so lution of stannic chloride for one hour then washing the fabric, treating the washed fabric with a solution of sodium phosphate for approximately one hour, then washing the fabric, treating the washed fabrics with a weak solution of acetic acid for approximately one half hour, washing the fabric with cold water, treating the fabric with a solution of lead acetate for approximately one hour, and then washing said fabric and treating the same with a cold solution of sodium phosphate'for approximately one half hour.

3. A process for weighting silk fabrics which comprises treating the fabrics with a solution of stannic chloride, then washing the fabrics, treating the washed fabrics with a solution of sodium phosphate, then washing the fabrics, treating the washed fabrics with a solution of acetic acid, then washing the fabrics with cold water, treating the fab rics with a solution of lead acetate, then washing the fabrics and treating the same with a cold solution of sodium phosphate.

4. A step in the process for weighting silk fabrics which comprises treating silk fabrics with a weak solution of acetic acid for approximately one half hour, washing the fabrics thus treated in cold water, then treating the washed fabrics with a solution of lead acetate for approximately one hour, washing said fabrics. and then treating said fabrics with a cold solution of sodium phosphate for approximately one half hour.

5. A step in the process for weighting silk fabrics which comprises treating silk fabrics with a hot solution of acetic acid for approximately one half hour, washing said fabrics in cold water and then treating the fabrics with a hot solution of lead acetate of approximately 8 Baum for approximately one hour, then washing the fabric and treating the same with a cold solution of sodium phosphate for approximately one half hour.

6. A step in the process for weighting silk fabrics which comprises treating silk fabrics with a weak solution of acetic acid, Washing the fabrics thus treated in cold water, then treating the washed fabrics with a solution of lead acetate, washing said fabrics and then treating said fabrics with a cold solution oi sodium phosphate.

7. A step in the process for weighti 11g silk fabrics which comprises treating silk fabrics with a. Weak Solution of acetic acid, treating essons the fabrics with a solution of lead acetate, and then treating the fabrics with a solution of sodium phosphate.

lnwitness whereof, I have hereunto set my hand this 20th day of February 1926. 15

OLAV BERG.

In witness whereof, I have hereunto set my hand this 20th day of February, 1926.

MAX lMHOF F. 

